Numerical prediction of portal hypertension by a hydrodynamic blood flow model combing with the fractal theory.

Portal hypertension (PH) can cause a series of complications, therefore, early prediction of PH is important. Traditional diagnostic methods are harmful to the human body, while other non-invasive methods are inaccurate and lack physical meaning. Combining various fractal theories and flow laws, we establish a complete portal system blood flow model from the Computed Tomography (CT) and angiography images. The portal vein pressure (PP) is obtained by the flow rate data from the Doppler ultrasound and the pressure-velocity relationship is established by the model. Three normal participants and 12 patients with portal hypertension were divided into three groups. For the three normal participants (Group A), their mean PP calculated by the model is 1752 Pa, falling into the normal range of PP. The mean PP of three patients with portal vein thrombosis (Group B) is 2357 Pa; and for the 9 patients with cirrhosis (Group C), their mean PP is 2915 Pa. These results validate the classification performance of the model. Moreover, the blood flow model can give early warning parameters of the corresponding portal vein trunk and portal vein microtubules for thrombosis and liver cirrhosis. This model presents the complete process of blood flow from sinusoids to the portal vein, adapts to the diagnosis of portal hypertension of thrombosis and liver cirrhosis, and provides a new method for noninvasive portal vein pressure detection from the perspective of biomechanics.

Effect of meal intake for evaluating hepatic artery by Doppler ultrasonography in liver transplants: Does fasting matter for screening hepatic artery due to hemodynamic changes in splanchnic circulation?

PURPOSE: The aim of this study is to assess the utility of fasting on Doppler ultrasonography findings of hepatic artery in liver transplants. METHODS: Liver transplant patients without vascular abnormalities were prospectively evaluated between December 2017 and January 2020. Doppler sonography was used to describe hemodynamic changes in response to a standard meal. The diameter, peak systolic velocity, blood flow, resistive index (RI) of the main hepatic artery and portal vein peak velocity were measured. RESULTS: The mean hepatic arterial diameter of 44 patients was higher in the fasting group (4.5 mm) than in the postprandial group (3.3 mm) (p < .05). The mean hepatic arterial blood flow decreased (from .276 to .127 L/min) and hepatic arterial RI increased (from .66 to .71) following meal ingestion (p < .05). Hepatic arterial velocity was significantly lower and portal venous velocity was higher after oral intake. CONCLUSION: Meal ingestion has an important effect on hepatic artery Doppler features in liver transplants. Therefore, Doppler ultrasound evaluation should be considered after appropriate fasting due to postprandial responses of liver transplant.

Liver Growth and Portal Hypertension Improvement After Percutaneous Recanalization of Chronic Portal Vein Thrombosis in Non-Cirrhotic Participants.

PURPOSE: To evaluate liver function improvement and volume gain after percutaneous recanalization of chronic portal vein thrombosis (PVT) in non-cirrhotic patients. MATERIALS AND METHODS: In this retrospective study, five non-cirrhotic participants between 21 and 67 years old with secondary chronic PVT (4-21 years from diagnose) were submitted to percutaneous portal vein recanalization, followed by varices and shunts embolization. RESULTS: After a mean of 12.6 months, all portal veins remained patent and there was complete resolution of portal hypertension (PH) symptoms in all participants. There was a significant increase in liver volume of 39.8 ± 19.0% (p = 0.042), platelets count of 53120 ± 20188/µl (p = 0.042), and a significant decrease in total bilirubin levels from 1.04 ± 0.23 mg/dL to 0.51 ± 0.09 mg/dL (p = 0.043). We also found a non-significant increase in albumin levels from 3.88 ± 0.39 g/dL to 4.38 ± 0.27 g/dL (p = 0.078) and decrease in spleen diameter from 16.88 ± 4.03 cm to 14.15 ± 2.72 cm (p = 0.068). DISCUSSION: In this retrospective study, even with a small number of participants, we were capable of showing a median of 39.8% increase in liver volume, laboratorial liver function improvement, platelets count and resolution of PH symptoms, including gastroesophageal varices disappearance after portal vein recanalization followed by shunt embolization. CONCLUSION: In this small series of cases, recanalization of chronic PVT in non-cirrhotic participants was feasible, successful and safe despite the prolonged time of occlusion. This is a new and promising approaching to an old and still challenging disease.

Does Arterialization of Portal Vein Have Any Effects in Large-for-Size Liver Transplantation? Hemodynamic, Histological, and Biomolecular Experimental Studies.

BACKGROUND: In pediatric liver transplantation, the optimal size of the transplanted liver ranges between 0.8% and 4.0% of the recipient's weight. Sometimes, the graft weight exceeds this upper limit, characterizing the large-for-size condition potentially associated with reduced blood flow and worsening of ischemia-reperfusion injury. Therefore, it would be beneficial to increase the portal flow through arterialization of the portal vein. Materials and methods: Fifteen pigs underwent large-for-size liver transplants. They were divided into two groups: control (CTRL 6 animals - conventional technique) and arterialization - a shunt was established between the portal vein and the splenic artery (ART 9 animals). Hemodynamic, biochemical, histological, and molecular variables were compared. Results: Arterialization resulted in a significant increase in portal vein pressure but no changes in other hemodynamic variables, as shown in the analysis of variance. It was observed lower ALT values (p = 0.007), with no differences regarding the values of blood pH and lactate (p = 0.54 and p = 0.699 respectively) or histological variables (edema, steatosis, inflammation, necrosis, and IRI - p = 1.0, p = 0.943, p = 0.174, p = 0.832, p = 0.662, respectively). The molecular studies showed significantly increased expression of IL6 after 3 hours of reperfusion (p = 0.048) and decreased expression of ICAM immediately after reperfusion (p = 0.03). The regression analysis suggested a positive influence of portal flow and pressure on biochemical parameters. Conclusion: Arterialization of the portal vein showed no histological, biochemical, or molecular benefits in large-for-size transplantation.

Water intake releases serotonin from enterochromaffin cells in rat jejunal villi.

The present study aims to investigate the roles of water intake in serotonin production and release in rat jejunum. We evaluated the changes in concentrations of serotonin in the portal vein and mesenteric lymph vessel induced by the intragastric administration of distilled water. The density of granules in enterochromaffin cells and the immunoreactivity of serotonin in the jejunal villi were investigated before and after water intake. The effects of intravenous administration of serotonin and/or ketanserin on mesenteric lymph flow and concentrations of albumin and IL-22 in the lymph were also addressed. Water intake increased serotonin concentration in the portal vein, but not in the mesenteric lymph vessel. The flux of serotonin through the portal vein was significantly larger than that through the mesenteric lymph vessel. Water intake decreased the density of granules in the enterochromaffin cells and increased the immunoreactivity of serotonin in the jejunal villi. The intravenous administration of serotonin increased significantly mesenteric lymph flow and the concentrations of albumin and IL-22; both were significantly reduced by the intravenous pretreatment with ketanserin. We showed that serotonin released from enterochromaffin cells by water intake was mainly transported through the portal vein. Additionally, serotonin in blood was found to increase mesenteric lymph formation with permeant albumin in the jejunal villi via the activation of 5-HT2 receptor.

Portal Venous Flow Is Increased by Jejunal but Not Colonic Hydrogen Sulfide in a Nitric Oxide-Dependent Fashion in Rats.

Hydrogen sulfide (H2S) is a recently discerned endogenous signaling molecule that modulates the vascular system. Endogenous hydrogen sulfide has been shown to dilate both the mesenteric and portal vasculature. Gut microbiome, via sulfur reducing bacteria, is another source of H2S production within the gut lumen; this source of H2S is primarily produced and detoxified in the colon under physiologic conditions. Nitric oxide (NO), a major endogenous vasodilator in the portal circulation, participates in H2S-induced vasodilation in some vascular beds. We hypothesize that jejunal but not colonic H2S increases portal vein flow in a NO-dependent fashion. To evaluate the effects of luminal H2S, venous blood flow, portal venous pressure, and systemic venous pressure were measured in rats after administration of either vehicle or an H2S donor (NaHS) into the jejunum or the colon. We found that portal venous pressure and systemic pressure did not change and were similar between the three study groups. However, portal venous blood flow significantly increased following jejunal administration of NaHS but not in response to colonic NaHS or vehicle administration. To test the contribution of NO production to this response, another group of animals was treated with either an NO synthase inhibitor (N-Ω-nitro-L-arginine, L-NNA) or saline prior to jejunal NaHS infusion. After L-NNA pretreatment, NaHS caused a significant fall rather than increase in portal venous flow compared to saline pretreatment. These data demonstrate that H2S within the small intestine significantly increases portal venous blood flow in a NO-dependent fashion.

Pediatric living donor left lateral segment liver transplantation for biliary atresia: Doppler ultrasound findings in early postoperative period.

PURPOSE: To analyze hepatic hemodynamic parameters detected by Doppler ultrasound (DU) of uncomplicated children with biliary atresia who underwent left lateral segment living donor liver transplantation (LLS-LDLT), explore its normal change trend over time and determine the normal reference interval. METHODS: We retrospectively involved the data from 227 biliary atresia patients (100 Males,127 Females). Hemodynamic parameters include peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI), and pulsation index (PI) of the hepatic artery (HA), portal vein velocity (PVV), portal vein flow (PVF) and hepatic vein velocity (HVV) during intra-operative and on the 1st, 3rd, 5th and 7th day after operation were collected. Repeated measures analysis of the variance and Friedman test were used to analyze the changing trend of hemodynamic parameters over time in the first week after the operation. RESULTS: PSVHA and EDVHA showed a similar changing tendency at one week after surgery, with an overall decrease-rise trend; RIHA and PIHA also changed similarly with an overall rise-decrease trend. The HVV and PVV at surgery were lower than at all time points after surgery. As for PVF, the value of POD5 was the highest and then decreased. Additionally, this study provided the normal reference interval of hemodynamic parameters for LLS-LDLT patients, which were PSVHA: 18.4-98.3 cm/s, EDVHA: 0-43.3 cm/s, RIHA: 0.41-1.0, PIHA: 0.51-2.0, PVV: 19.0-83.7 cm/s, HVV: 19.4-68.0 cm/s, and PVF:99.5-500.0 ml/min/100 g at intraoperation. Within the first postoperative week: PSVHA: 21.0-97.7 cm/s, EDVHA: 0-32.7 cm/s, RIHA: 0.47-1.0, PIHA: 0.62-2.0, PVV: 23.0-92.0 cm/s, HVV: 19.7-86.0 cm/s, and PVF: 100.0-513.0 ml/min/100 g. CONCLUSION: The hepatic hemodynamic of post-transplanted children detected by DU had specific changing trends and normal ranges, which provides valuable reference values for ultrasonologists and pediatric transplant clinicians.

Influence of interapplicator distance on multibipolar radiofrequency ablation during physiological and interrupted liver perfusion in an in vivo porcine model.

Radiofrequency ablation (RFA) is a curative treatment option for early stage hepatocellular carcinoma (HCC). Vascular inflow occlusion to the liver (Pringle manoeuvre) and multibipolar RFA (mbRFA) represent possibilities to generate large ablations. This study evaluated the impact of different interapplicator distances and a Pringle manoeuvre on ablation area and geometry of mbRFA. 24 mbRFA were planned in porcine livers in vivo. Test series with continuous blood flow had an interapplicator distance of 20 mm and 15 mm, respectively. For a Pringle manoeuvre, interapplicator distance was predefined at 20 mm. After liver dissection, ablation area and geometry were analysed macroscopically and histologically. Confluent and homogenous ablations could be achieved with a Pringle manoeuvre and an interapplicator distance of 15 mm with sustained hepatic blood flow. Ablation geometry was inhomogeneous with an applicator distance of 20 mm with physiological liver perfusion. A Pringle manoeuvre led to a fourfold increase in ablation area in comparison to sustained hepatic blood flow (p < 0.001). Interapplicator distance affects ablation geometry of mbRFA. Strict adherence to the planned applicator distance is advisable under continuous blood flow. The application of a Pringle manoeuvre should be considered when compliance with the interapplicator distance cannot be guaranteed.

Evaluation of abdominal hemodynamics through compressed sensing accelerated functional imaging.

PURPOSE: To compare the imaging characteristics of the volumetric-interpolated breath-hold examination (VIBE) using compressed-sensing (CS) acceleration (CS-VIBE) with the conventional sequence relying on parallel imaging to assess the potential use of CS-VIBE as a functional imaging technique for upper abdominal haemodynamics. MATERIALS AND METHODS: Patients (30 men, 27 women) suspected of having a hepatic disease underwent magnetic resonance imaging (MRI) of the liver, including a dynamic contrast-enhanced study. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid was used as the contrast agent. MRI data of two multi-phase breath-hold exams were used for intra-individual comparisons. The VIBE and CS-VIBE were performed on different days. Image quality in both sequences was qualitatively assessed by three experienced radiologists. Moreover, the contrast ratio (CR) of the aorta, portal vein, liver and pancreas to muscle tissue were measured as a quantitative assessment. For the CS-VIBE, a five-phase time-intensity curve (TIC) was created to evaluate haemodynamics. The measurement area included the pancreas, common hepatic artery, portal vein and superior mesenteric vein. The ratio of that area to the muscle tissue in the same cross section was used to create the TICs. RESULTS: The qualitative assessment showed that artefacts were significantly different between the VIBE and CS-VIBE sequences. This finding indicated that the conventional VIBE had fewer artefacts. The CR was significantly higher for the CS-VIBE than for the VIBE images in all phases (p < 0.001). An evaluation of haemodynamics compared with those obtained by CT angiography showed almost the same temporal characteristics in the common hepatic artery, portal vein and superior mesenteric vein signals as those in a previous study. CONCLUSION: Compared with the conventional VIBE, the CS-VIBE had significantly higher temporal resolution and higher image contrast. The temporal resolution of the CS-VIBE was sufficient for viewing abdominal haemodynamics. If the remaining limitation of acquisition speed for dynamic MRI can be adequately addressed, we believe that CS-VIBE functional images with high-contrast haemodynamics will be very useful in clinical practise.

An ultrasound-based referential of body height-adjusted normal liver organometry in school children from Bokito in rural Cameroon.

The grading system for ultrasonographic assessment of Schistosoma mansoni morbidity is crucial for evaluation of control programs. This requires prior definition of normal liver organometric ranges in the population from the endemic area. A cross-sectional study was conducted in a S. mansoni endemic area in rural Cameroon. 1002 Participants were screened and 234 of them, free from all common liver-affecting diseases in the area (schistosomiasis, malaria, hepatitis B and C) and with no ultrasonographic signs of liver disease were selected and their liver parameters measured by ultrasonography. All statistics were considered significant for p-values < 0.05. Normal dimensions of livers lobe sizes, portal vein wall thickness and portal vein diameters are reported. The liver organometric data are presented for the entire study population as a whole and separately for males and females as prediction plots, with observed values and fitted regression line with 95% confidence. Reference ranges for liver parameters (size, portal vein thickness and diameter) adjusted for body height established in the current study are novel for Cameroon. The prediction plots generated should improve the accuracy of the assessment of liver morbidity by ultrasonography in the region.

Partial orthotopic liver transplantation in combination with two-stage hepatectomy: A proof-of-concept explained by mathematical modeling.

BACKGROUND: Resection And Partial Liver Segment 2/3 Transplantation with Delayed total hepatectomy (RAPID) includes total hepatectomy in 2 steps with small graft transplantation at first stage. To avoid graft portal hyperperfusion, portal vein pressure monitoring is required after revascularization and right portal vein clamping. To date, portal flow modulation has not been reported but simulating hemodynamics in RAPID patients would be useful to anticipate these procedures. Our team developed hemodynamic 0D modeling; we aimed to assess if this mathematical model could be accurately used in the RAPID setting. METHODS: The modified 0D model was retrospectively tested on 3 patients. We compared our estimated portal vein pressures and portocaval gradients to those intraoperatively measured, as indication to modulate portal flow relies on these measures. FINDINGS: Portal pressures measured after right portal vein clamping (end of RAPID procedure) in patients 1, 2 and 3 were respectively of 14, 16 and 12 mmHg while the simulated pressures were of 13.1, 14.8 and 11.5 mmHg (p = 0.25). Portocaval gradients measured after right portal vein clamping in the 3 patients were respectively of 10, 11 and 7 mmHg while the simulated gradients were of 9.9, 11.6 and 8.3 mmHg (p = 0.5). INTERPRETATION: We succeeded to predict portal vein pressures and portocaval gradients after RAPID. This promising report demonstrates that 0D simulation could be a useful tool for human decision-making. Moreover, such a patient-specific model could be of importance if we transpose RAPID experience to hepatocellular carcinoma bearing cirrhotics, a population with high probability of portal hypertension after RAPID.

The "streamline phenomenon" of the portal vein flow and its influence on liver involvement by gastrointestinal diseases: current concepts and imaging-based review.

The streamline flow in the portal system is a phenomenon by which blood from superior mesenteric vein goes preferentially to the right hepatic lobe, while splenic and inferior mesenteric veins divert preferentially to the left lobe. Such a phenomenon results in different patterns of distribution of several liver diseases. The purpose of this article is to discuss the concepts behind the theory of streamline flow and to perform an imaging-based review of representative cases, demonstrating how it may influence the patterns of liver involvement in different gastrointestinal diseases.

Allogeneic Venous Grafts of Different Origin Used for Portal Vein Reconstruction After Pancreaticoduodenectomy - Experimental Study.

BACKGROUND: In clinical medicine, little is known about the use of allografts for portal vein (PV) reconstruction after pancreaticoduodenectomy (PD). Portal and caval systems are physiologically different, therefore the properties of allografts from caval and portal systems were studied here in a pig model. MATERIALS AND METHODS: PD with PV reconstruction with allogeneic venous graft from PV or inferior vena cava (IVC) was performed in 26 pigs. Biochemical analysis and ultrasonography measurements were performed during a 4-week monitoring period. Computer simulations were used to evaluate haemodynamics in reconstructed PV and explanted allografts were histologically examined. RESULTS: The native PV and IVC grafts varied in histological structure but were able to adapt morphologically after transplantation. Computer simulation suggested PV grafts to be more susceptible to thrombosis development. Thrombosis of reconstructed PV occurred in four out of five cases in PV group. CONCLUSION: This study supports the use of allografts from caval system for PV reconstruction in clinical medicine when needed.

Effect of Remote Ischemic Preconditioning in Patients Undergoing Hepatectomy With Portal Triad Clamping: A Randomized Controlled Trial.

BACKGROUND: Remote ischemic preconditioning (RIPC) is reported to reduce liver injury in patients undergoing hepatectomy for colorectal liver metastasis, but its role is unclear in hepatocellular carcinoma patients with portal triad clamping during hepatectomy. METHODS: In this prospective, randomized trial, 140 patients with hepatocellular carcinoma undergoing liver resection requiring portal triad clamping were randomized to a RIPC group or a control group. Patients in the RIPC group received RIPC (3 cycles of 5-minute ischemia and 5-minute reperfusion in right upper limb with cuff pressure at 30 kPa [225 mm Hg]) approximately 10 minutes after induction of anesthesia. In the control group, patients received sham RIPC (the cuff was not inflated). The primary outcome was the postoperative peak level of total bilirubin (TBIL) and was analyzed with the independent t test. Secondary outcomes were liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay. RESULTS: Data from 136 patients (69 in the RIPC group and 67 in the control group) were analyzed. The RIPC group had on average a 5.9 µmol lower peak level of TBIL than the control group; the mean difference is -5.9, and the 95% confidence interval (CI) reverses to -17.9 to 6.1. There were no significant differences between the 2 groups in liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay. CONCLUSIONS: We found no evidence that RIPC can reduce postoperative liver injury after hepatectomy.

Measurement of Exhaled Nitric Oxide in Cirrhotic Patients with Esophageal and Gastric Varices.

Background and aims. This study aimed to detect exhaled nitric oxide (eNO) level in cirrhotic patients and explore the correlation between eNO levels and the severity of cirrhosis. Methods. Patients were enrolled to analyze the relationship of eNO with noncirrhosis, cirrhosis, and complications of decompensated cirrhosis. We explored the potential predictive values of eNO in different states of cirrhosis. Results. The eNO levels were significantly increased in cirrhotic patients compared with noncirrhotic patients (14 (10-18) vs 8 (6-13) ppb, P < 0.001). The eNO level was increased in those with ascites (15 (14-22) vs 13 (10-18) ppb, P=0.026), with portal vein thrombosis (19.5 (11.75-22) vs 13.5 (10-17) ppb, P=0.032), or with the mucosal red-color sign of esophageal and gastric varices (EGV) (16.5 (10-21.75) vs 13 (10-14.75) ppb, P=0.041). Among cirrhotic patients undergoing hepatic venous pressure gradient (HVPG) measurement, the eNO level was significantly increased in the high-HVPG group (HVPG >12 mm Hg) compared with the low-HVPG group (6 mm Hg ≤ HVPG ≤ 12 mm Hg) (15 (11.75-19.25) vs 10 (8-14) ppb, P=0.011). Conclusions. The eNO level was increased in cirrhotic patients, especially in those complicated with ascites, portal vein thrombosis, mucosal red-color sign of varices, and high HVPG.

Microvascular proliferation of the portal vein branches in the liver of biliary atresia patients at Kasai operation is associated with a better long-term clinical outcome.

AIM OF THE STUDY: We previously showed an increased number of smaller portal vein (PV) branches in the portal areas of liver biopsy specimens of biliary atresia (BA) patients. We evaluated the correlation between this histopathological feature and the prognosis. PATIENTS AND METHODS: Twenty-five consecutive patients with BA encountered between 2000 and 2012 were classified into three prognostic groups based on their postoperative outcomes: Excellent (n = 11) for native-liver survivors with a normal liver function, Good (n = 6) for native-liver survivors with liver dysfunction, and Poor (n = 8) for survivors after liver transplant or on a waiting list. Data from morphometrical analyses, including the fibrotic portal area, numbers of PVs, diameter and total area of PV branches, were statistically compared among the three groups. MAIN RESULTS: The number of PV branches per unit area of the whole-liver specimen in the poor prognostic group was significantly lower than that in the excellent group (3.1 ± 0.6 vs. 5.2 ± 2.0/mm2, p = 0.03). There were no significant differences in the other parameters. CONCLUSIONS: This is the first report on the relationships between morphometrically analyzed PV branches and the postoperative course in BA patients. The portal venous system is involved as the primary lesion in BA.

Anatomically based simulation of hepatic perfusion in the human liver.

Liver structures of a healthy subject are digitised and segmented from computed tomography (CT) images, and hepatic perfusion is modelled in the hepatic artery and portal vein of the healthy subject with structured tree-based outflow boundary conditions. This self-similar structured tree is widely used in the literature, eg, blood flow simulation in larger systemic arteries and cerebral circulation, and is used in this study to model the effect of the smaller hepatic arteries and arterioles, as well as the smaller hepatic portal veins and portal venules. Physiologically reasonable results are obtained. Since the structured tree terminates at the size of the microvasculature system in liver lobules, the structured tree boundary condition will enable the proposed organ-level model of hepatic arterial flow to be easily connected to tissue-level models of liver lobules. Blood flow in the hepatic vein is also modelled in this subject with three-element Windkessel model as outflow boundary conditions. The benefit of integrating the perfusion in all hepatic vascular vessels is that it helps us analyse some complicated clinical phenomenon more efficiently, eg, one possible application is to obtain the portal pressure gradient (PPG) to help examine the reliability of hepatic venous pressure gradient (HVPG) as an indirect measure of portal pressure. Moreover, since four to six generations of hepatic vessels, which are sufficient for liver classification analysis, were employed in the model, this study is setting the computational foundation of a potentially handy surgical tool.

Magnetic Resonance Imaging Assessment of Blood Flow Distribution in Fenestrated and Completed Fontan Circulation with Special Emphasis on Abdominal Blood Flow.

OBJECTIVE: To investigate the regional flow distribution in patients with Fontan circulation by using magnetic resonance imaging (MRI). MATERIALS AND METHODS: We identified 39 children (18 females and 21 males; mean age, 9.3 years; age range, 3.3-17.0 years) with Fontan circulation in whom flow volumes across the thoracic and abdominal arteries and veins were measured by using MRI. The patients were divided into three groups: fenestrated Fontan circulation group with MRI performed under general anesthesia (GA) (Group 1, 15 patients; average age, 5.9 years), completed Fontan circulation group with MRI performed under GA (Group 2, 6 patients; average age, 8.7 years), and completed Fontan circulation group with MRI performed without GA (Group 3, 18 patients; average age, 12.5 years). The patient data were compared with the reference ranges in healthy controls. RESULTS: In comparison with the controls, Group 1 showed normal cardiac output (3.92 ± 0.40 vs. 3.72 ± 0.69 L/min/m², p = 0.30), while Group 3 showed decreased cardiac output (3.24 ± 0.71 vs. 3.96 ± 0.64 L/min/m², p = 0.003). Groups 1 and 3 showed reduced abdominal flow (1.21 ± 0.28 vs. 2.37 ± 0.45 L/min/m², p < 0.001 and 1.89 ± 0.39 vs. 2.64 ± 0.38 L/min/m², p < 0.001, respectively), which was mainly due to the diversion of the cardiac output to the aortopulmonary collaterals in Group 1 and the reduced cardiac output in Group 3. Superior mesenteric and portal venous flows were more severely reduced in Group 3 than in Group 1 (ratios between the flow volumes of the patients and healthy controls was 0.26 and 0.37 in Group 3 and 0.63 and 0.53 in Group 1, respectively). Hepatic arterial flow was decreased in Group 1 (0.11 ± 0.22 vs. 0.34 ± 0.38 L/min/m², p = 0.04) and markedly increased in Group 3 (0.38 ± 0.22 vs. -0.08 ± 0.29 L/min/m², p < 0.0001). Group 2 showed a mixture of the patterns seen in Groups 1 and 3. CONCLUSION: Fontan circulation is associated with reduced abdominal flow, which can be attributed to reduced cardiac output and portal venous return in completed Fontan circulation, and diversion of the cardiac output to the aortopulmonary collaterals in fenestrated Fontan circulation.

Effect of Portal Venous Pressure on Liver Function of Donors in Living Donor Liver Transplantation.

BACKGROUND We assessed the alterations in portal hemodynamics associated with donor right hepatectomy and its effects on functional regeneration of the remnant liver. MATERIAL AND METHODS This prospective study included 30 adult living donors who underwent right hepatectomy in the Liver Transplantation Unit, Faculty of Medicine, Cairo University from June 2015 to October 2016. During donor surgery, portal venous pressure (PVP) was measured using an antithrombotic catheter inserted into the main portal vein, and was measured before and after clamping of the right portal vein. Postoperatively, liver function tests were done daily until normalization. The outcome measures were the time to normalization of liver function tests and effect of residual volume and steatosis on PVP. RESULTS All donors had normal PVP before clamping and changed significantly after clamping (p<0.001). After clamping, 25 donors (83%) had a PVP above 12 mmHg; i.e. had high portal pressure. The median percentage of change was 55%. There were obvious increases in liver enzymes and bilirubin after surgery, but albumin and international normalized ratio showed progressive decreases postoperatively. The percent change in PVP was positively correlated with the levels of liver enzymes, time to normalization of liver enzymes, albumin, and bilirubin, and with the degree of steatosis, bit it was negatively correlated with residual liver volume. CONCLUSIONS During living donor liver transplantation, PVP increases by over 50% after clamping of the right portal vein of the donor's liver. This increase is associated with temporary delay of normalization of liver function of the donors.